ORA-29285: file write error

t_clob_len := DBMS_LOB.GetLength(p_data);

        t_out_file := UTL_FILE.fOpen(p_dir,p_file, 'A', 32767);
        LOOP
            DBMS_LOB.Read(p_data,t_amount,t_pos, t_buffer);
            Utl_File.Put(T_Out_File, T_Buffer);
            
            Utl_File.Fflush(T_Out_File);

            t_pos := t_pos + t_amount;
            IF t_clob_len<=t_pos THEN
                exit;
            END IF;
        END LOOP;

  UTL_FILE.fClose(t_out_file);

But i am getting following error at Utl_File.Fflush(T_Out_File); Method while looping at 3rd time .

error:=ORA-29285: file write error

Please Suggest any Solution.